1. Field of the Invention
The present invention relates to a toy construction kit comprising small and large building blocks having a hollow open ended box-like base with cylindrical outer couplers and cylindrical inner couplers These blocks cannot be coupled directly together and the kit provides a further block suitable to join them.
2. Description of the Prior Art
The original toy building blocks or bricks of the above general type, better known under the trade mark LEGO and disclosed in U.S. Pat. No. 3,005,282 of Oct. 24, 1961, both in the name of INTERLEGO A.G. are relatively small and are of interest particularly to older children because they are somewhat difficult to handle and to use. A possible disadvantage also is that a large number of them is required if a structure of any reasonable size is to be built. For these reasons, a large block has been devised to be associated and to cooperate to the LEGO block. It is known under the trade mark DUPLO and is the subject of U.S. Pat. No. 3,597,875 of Aug. 10, 1971, both of said trade mark and patent also belonging to INTERLEGO A.G.
More recently, much larger blocks, known under the trade mark MEGA BLOK (see U.S. Pat. No. 4,740,189 of Apr. 26, 1988 to the present Applicant) have come on the market and are quite popular with younger children because of their facility to be handled and used. However, when the child has grown up and has become interested in the DUPLO and LEGO blocks, the MEGA BLOK blocks have to be discarded although they could still be of much interest in certain structures. They have to be set aside because they are not adapted to be coupled with the DUPLO blocks. If the MEGA BLOK block was so adapted, the DUPLO block would then act as an intermediary between the MEGA and LEGO blocks.
Although there are numerous copies of the DUPLO and LEGO blocks presently available in the market under other trade marks such as, for example, TYCO, all the toy construction blocks referred to hereinafter will be identified by the above mentioned trade marks of INTERLEGO A.G., exclusively for simplicity's sake.